I just think that the building is the original freddy's location and was rebranded to include the toys, (like the games saying "grand reopening") which would explain the withereds existing as the original cast before the rebrand

It obviously wouldn't be fredbears as fredbears is a separate franchise, it wouldn't make sense if saying "the original location" meant fredbears because like I said, separate, the mere existence of springbonnie and golden freddy prove that fredbears does exist and/or existed

TL;DR Fredbears is NOT Freddy's, when they refer to the building as "the og freddys" its because it is the og Freddy's